Method of utilizing feldspar.



J. G. A. RHODIN.

METHOD OF UTILIZING FELDSPAR. APPLICATION FILED DEC. 4. m5.

PatentedJuly 10, 1917.

.- the contact process of sulfuric acid manufacture; I

stoke up the furnace and raise the temperatimes be necessary. Thr ground material ture to complete the reaction, but by suitshould leave practically no residue on a ably adjusting all factors the time for the 180 mesh standard cement sieve. Acceleratdecomposing of a thin layer of powdered ing salt, 6. 9. common salt or sodium chlorid spar should not exceed one hour. The gases is preferably added by impregnating the are then turned off and the charge is drawn, feldspar powder with a solution of the salt. the furnace being of course re-started with In most cases half per cent. by weight is a new charge immediately.

added to the feldspar with just enough wa- The drawn charge is lixiviated with water to make the whole mass damp, although, ter and the potassium sulfate is recovered by as previously stated, the amount of salt will evaporation.

in nocase have to exceed two per cent. The

retort A of impervious acid-proof eartheneither of dry slaked lime or ground limeware, having at' one end a charging and stone, neither of whichshou ld contain any discharging door B. The retort is mounted coloring oxids. The proportions depend in a furnace C of the reverberatory type. upon whether it is desired to make a Roman At the rear or charging and discharging or a Portland cement. For whiteness :1 end, inlet tubes D are provided for the gas Roman cement containing fifty per cent. of mixture, while at the other end of the re- GaO is preferable, but an addition of twotort at E a suitable connection is made with and-a-half per cent. of alum or ofa corre condensing plant F. sponding quantity of lime cake is essential.

In operation a charge G of salt impreg- A Portland cement may be made in the natecl spar is put into the retort which is. 'usual way, clinkered and ground, but it will kept at very dull red heat fora suitable always retain a greenish tint. time, while a mixture of sulfurous acid, I-claim: steam, and air is passed over the charge. 1. The method of utilizing potash feld- The time .of reaction varies with several fac- Spar which consists in mixing the ground tors such as the actual composition of the feldspar with a small quantity of a sodium gas mixture, the temperature, and the finesalt, causing a mixture of' sulfur dioxid, ness of division of the mineral. With resteam and air to react on .the heated mixgard to the composition of the gas mixture, ture, collecting the sulfuric acid formed in this will carry more or less nitrogen accordsuitable receivers and leachingthe residue so ing to the working of the pyrites or brimas to obtain sulfate of potash and to leave stone burners which will obviously be necesa residue suitable for making white Roman sary. For this reason it would be preferor Portland cement.

able to work with pure sulfur di-oxid, but 2. The method of utilizing potash feldfor economic reasons this will seldom be spar which consists in mixing the ground practicable. Further, the feldspar itself vafeldspar with a small quantity of sodium ries in diii'erent localities, and the orthoclase -chlorid, causing a mixture of sulfur dioxid, is in many places impregnated with various steam and air to react on the heated mixture forms of soda spar. It should be pointed collecting the sulfuric acid formed in suitoutjthat the more closely the chemical comable receivers and leaching the residue so positionof the spar approaches that of pure as to obtain sulfate of potash, and to leave gor'thoclase, the more suited the mineral will a residue suitable for making white Roman be for the purposes of this invention. The or' Portland cement.

gas mixture is made and adjusted in any In testimony whereof I aflix my signature of the well known types of plant used for in presence of two witnesses.

JOHN GUSTAF ADOLF RHODIN. Witnesses:

FRANK B. DEHN, ALBERT R. RAMSEY.

' In some cases it may be necessary to The white acid aluminum'silicate residue "mass is then charged into a simple tubular 1s made into cement slurry with the addition 

